minijinja/value/mod.rs
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//! Provides a dynamic value type abstraction.
//!
//! This module gives access to a dynamically typed value which is used by
//! the template engine during execution.
//!
//! For the most part the existence of the value type can be ignored as
//! MiniJinja will perform the necessary conversions for you. For instance
//! if you write a filter that converts a string you can directly declare the
//! filter to take a [`String`]. However for some more advanced use cases it's
//! useful to know that this type exists.
//!
//! # Basic Value Conversions
//!
//! Values are typically created via the [`From`] trait:
//!
//! ```
//! use std::collections::BTreeMap;
//! # use minijinja::value::Value;
//! let int_value = Value::from(42);
//! let none_value = Value::from(());
//! let true_value = Value::from(true);
//! let map = Value::from({
//! let mut m = BTreeMap::new();
//! m.insert("foo", 1);
//! m.insert("bar", 2);
//! m
//! });
//! ```
//!
//! Or via the [`FromIterator`] trait which can create sequences or maps. When
//! given a tuple it creates maps, otherwise it makes a sequence.
//!
//! ```
//! # use minijinja::value::Value;
//! // collection into a sequence
//! let value: Value = (1..10).into_iter().collect();
//!
//! // collection into a map
//! let value: Value = [("key", "value")].into_iter().collect();
//! ```
//!
//! For certain types of iterators (`Send` + `Sync` + `'static`) it's also
//! possible to make the value lazily iterate over the value by using the
//! [`Value::make_iterable`] function instead. Whenever the value requires
//! iteration, the function is called to create that iterator.
//!
//! ```
//! # use minijinja::value::Value;
//! let value: Value = Value::make_iterable(|| 1..10);
//! ```
//!
//! To to into the inverse directly the various [`TryFrom`]
//! implementations can be used:
//!
//! ```
//! # use minijinja::value::Value;
//! use std::convert::TryFrom;
//! let v = u64::try_from(Value::from(42)).unwrap();
//! ```
//!
//! The special [`Undefined`](Value::UNDEFINED) value also exists but does not
//! have a rust equivalent. It can be created via the [`UNDEFINED`](Value::UNDEFINED)
//! constant.
//!
//! # Collections
//!
//! The standard library's collection types such as
//! [`HashMap`](std::collections::HashMap), [`Vec`] and various others from the
//! collections module are implemented are objects. There is a cavet here which is
//! that maps can only have string or [`Value`] as key. The values in the collections
//! are lazily converted into value when accessed or iterated over. These types can
//! be constructed either from [`Value::from`] or [`Value::from_object`]. Because the
//! types are boxed unchanged, you can also downcast them.
//!
//! ```rust
//! # use minijinja::Value;
//! let vec = Value::from(vec![1i32, 2, 3, 4]);
//! let vec_ref = vec.downcast_object_ref::<Vec<i32>>().unwrap();
//! assert_eq!(vec_ref, &vec![1, 2, 3, 4]);
//! ```
//!
//! **Caveat:** for convenience reasons maps with `&str` keys can be stored. The keys
//! however are converted into `Arc<str>`.
//!
//! # Serde Conversions
//!
//! MiniJinja will usually however create values via an indirection via [`serde`] when
//! a template is rendered or an expression is evaluated. This can also be
//! triggered manually by using the [`Value::from_serialize`] method:
//!
//! ```
//! # use minijinja::value::Value;
//! let value = Value::from_serialize(&[1, 2, 3]);
//! ```
//!
//! The inverse of that operation is to pass a value directly as serializer to
//! a type that supports deserialization. This requires the `deserialization`
//! feature.
//!
#![cfg_attr(
feature = "deserialization",
doc = r"
```
# use minijinja::value::Value;
use serde::Deserialize;
let value = Value::from(vec![1, 2, 3]);
let vec = Vec::<i32>::deserialize(value).unwrap();
```
"
)]
//!
//! # Value Function Arguments
//!
//! [Filters](crate::filters) and [tests](crate::tests) can take values as arguments
//! but optionally also rust types directly. This conversion for function arguments
//! is performed by the [`FunctionArgs`] and related traits ([`ArgType`], [`FunctionResult`]).
//!
//! # Memory Management
//!
//! Values are immutable objects which are internally reference counted which
//! means they can be copied relatively cheaply. Special care must be taken
//! so that cycles are not created to avoid causing memory leaks.
//!
//! # HTML Escaping
//!
//! MiniJinja inherits the general desire to be clever about escaping. For this
//! purpose a value will (when auto escaping is enabled) always be escaped. To
//! prevent this behavior the [`safe`](crate::filters::safe) filter can be used
//! in the template. Outside of templates the [`Value::from_safe_string`] method
//! can be used to achieve the same result.
//!
//! # Dynamic Objects
//!
//! Values can also hold "dynamic" objects. These are objects which implement the
//! [`Object`] trait. These can be used to implement dynamic functionality such
//! as stateful values and more. Dynamic objects are internally also used to
//! implement the special `loop` variable, macros and similar things.
//!
//! To create a [`Value`] from a dynamic object use [`Value::from_object`],
//! [`Value::from_dyn_object`]:
//!
//! ```rust
//! # use std::sync::Arc;
//! # use minijinja::value::{Value, Object, DynObject};
//! #[derive(Debug)]
//! struct Foo;
//!
//! impl Object for Foo {
//! /* implementation */
//! }
//!
//! let value = Value::from_object(Foo);
//! let value = Value::from_dyn_object(Arc::new(Foo));
//! ```
//!
//! # Invalid Values
//!
//! MiniJinja knows the concept of an "invalid value". These are rare in practice
//! and should not be used, but they are needed in some situations. An invalid value
//! looks like a value but working with that value in the context of the engine will
//! fail in most situations. In principle an invalid value is a value that holds an
//! error internally. It's created with [`From`]:
//!
//! ```
//! use minijinja::{Value, Error, ErrorKind};
//! let error = Error::new(ErrorKind::InvalidOperation, "failed to generate an item");
//! let invalid_value = Value::from(error);
//! ```
//!
//! Invalid values are typically encountered in the following situations:
//!
//! - serialization fails with an error: this is the case when a value is crated
//! via [`Value::from_serialize`] and the underlying [`Serialize`] implementation
//! fails with an error.
//! - fallible iteration: there might be situations where an iterator cannot indicate
//! failure ahead of iteration and must abort. In that case the only option an
//! iterator in MiniJinja has is to create an invalid value.
//!
//! It's generally recommende to ignore the existence of invalid objects and let them
//! fail naturally as they are encountered.
//!
//! # Notes on Bytes and Strings
//!
//! Usually one would pass strings to templates as Jinja is entirely based on string
//! rendering. However there are situations where it can be useful to pass bytes instead.
//! As such MiniJinja allows a value type to carry bytes even though there is no syntax
//! within the template language to create a byte literal.
//!
//! When rendering bytes as strings, MiniJinja will attempt to interpret them as
//! lossy utf-8. This is a bit different to Jinja2 which in Python 3 stopped
//! rendering byte strings as strings. This is an intentional change that was
//! deemed acceptable given how infrequently bytes are used but how relatively
//! commonly bytes are often holding "almost utf-8" in templates. Most
//! conversions to strings also will do almost the same. The debug rendering of
//! bytes however is different and bytes are not iterable. Like strings however
//! they can be sliced and indexed, but they will be sliced by bytes and not by
//! characters.
// this module is based on the content module in insta which in turn is based
// on the content module in serde::private::ser.
use core::str;
use std::cell::{Cell, RefCell};
use std::cmp::Ordering;
use std::collections::BTreeMap;
use std::fmt;
use std::hash::{Hash, Hasher};
use std::sync::{Arc, Mutex};
use serde::ser::{Serialize, Serializer};
use crate::error::{Error, ErrorKind};
use crate::functions;
use crate::utils::OnDrop;
use crate::value::ops::as_f64;
use crate::value::serialize::transform;
use crate::vm::State;
pub use crate::value::argtypes::{from_args, ArgType, FunctionArgs, FunctionResult, Kwargs, Rest};
pub use crate::value::object::{DynObject, Enumerator, Object, ObjectExt, ObjectRepr};
#[macro_use]
mod type_erase;
mod argtypes;
#[cfg(feature = "deserialization")]
mod deserialize;
pub(crate) mod merge_object;
pub(crate) mod namespace_object;
mod object;
pub(crate) mod ops;
mod serialize;
#[cfg(feature = "key_interning")]
mod string_interning;
#[cfg(feature = "deserialization")]
pub use self::deserialize::ViaDeserialize;
// We use in-band signalling to roundtrip some internal values. This is
// not ideal but unfortunately there is no better system in serde today.
const VALUE_HANDLE_MARKER: &str = "\x01__minijinja_ValueHandle";
#[cfg(feature = "preserve_order")]
pub(crate) type ValueMap = indexmap::IndexMap<Value, Value>;
#[cfg(not(feature = "preserve_order"))]
pub(crate) type ValueMap = std::collections::BTreeMap<Value, Value>;
#[inline(always)]
pub(crate) fn value_map_with_capacity(capacity: usize) -> ValueMap {
#[cfg(not(feature = "preserve_order"))]
{
let _ = capacity;
ValueMap::new()
}
#[cfg(feature = "preserve_order")]
{
ValueMap::with_capacity(crate::utils::untrusted_size_hint(capacity))
}
}
thread_local! {
static INTERNAL_SERIALIZATION: Cell<bool> = const { Cell::new(false) };
// This should be an AtomicU64 but sadly 32bit targets do not necessarily have
// AtomicU64 available.
static LAST_VALUE_HANDLE: Cell<u32> = const { Cell::new(0) };
static VALUE_HANDLES: RefCell<BTreeMap<u32, Value>> = RefCell::new(BTreeMap::new());
}
/// Function that returns true when serialization for [`Value`] is taking place.
///
/// MiniJinja internally creates [`Value`] objects from all values passed to the
/// engine. It does this by going through the regular serde serialization trait.
/// In some cases users might want to customize the serialization specifically for
/// MiniJinja because they want to tune the object for the template engine
/// independently of what is normally serialized to disk.
///
/// This function returns `true` when MiniJinja is serializing to [`Value`] and
/// `false` otherwise. You can call this within your own [`Serialize`]
/// implementation to change the output format.
///
/// This is particularly useful as serialization for MiniJinja does not need to
/// support deserialization. So it becomes possible to completely change what
/// gets sent there, even at the cost of serializing something that cannot be
/// deserialized.
pub fn serializing_for_value() -> bool {
INTERNAL_SERIALIZATION.with(|flag| flag.get())
}
/// Enables value optimizations.
///
/// If `key_interning` is enabled, this turns on that feature, otherwise
/// it becomes a noop.
#[inline(always)]
pub(crate) fn value_optimization() -> impl Drop {
#[cfg(feature = "key_interning")]
{
crate::value::string_interning::use_string_cache()
}
#[cfg(not(feature = "key_interning"))]
{
OnDrop::new(|| {})
}
}
fn mark_internal_serialization() -> impl Drop {
let old = INTERNAL_SERIALIZATION.with(|flag| {
let old = flag.get();
flag.set(true);
old
});
OnDrop::new(move || {
if !old {
INTERNAL_SERIALIZATION.with(|flag| flag.set(false));
}
})
}
/// Describes the kind of value.
#[derive(Copy, Clone, Debug, Eq, PartialEq, Ord, PartialOrd)]
#[non_exhaustive]
pub enum ValueKind {
/// The value is undefined
Undefined,
/// The value is the none singleton (`()`)
None,
/// The value is a [`bool`]
Bool,
/// The value is a number of a supported type.
Number,
/// The value is a string.
String,
/// The value is a byte array.
Bytes,
/// The value is an array of other values.
Seq,
/// The value is a key/value mapping.
Map,
/// An iterable
Iterable,
/// A plain object without specific behavior.
Plain,
/// This value is invalid (holds an error).
///
/// This can happen when a serialization error occurred or the engine
/// encountered a failure in a place where an error can otherwise not
/// be produced. Interacting with such values in the context of the
/// template evaluation process will attempt to propagate the error.
Invalid,
}
impl fmt::Display for ValueKind {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.write_str(match *self {
ValueKind::Undefined => "undefined",
ValueKind::None => "none",
ValueKind::Bool => "bool",
ValueKind::Number => "number",
ValueKind::String => "string",
ValueKind::Bytes => "bytes",
ValueKind::Seq => "sequence",
ValueKind::Map => "map",
ValueKind::Iterable => "iterator",
ValueKind::Plain => "plain object",
ValueKind::Invalid => "invalid value",
})
}
}
/// Type type of string
#[derive(Copy, Clone, Debug)]
pub(crate) enum StringType {
Normal,
Safe,
}
/// Wraps an internal copyable value but marks it as packed.
///
/// This is used for `i128`/`u128` in the value repr to avoid
/// the excessive 16 byte alignment.
#[derive(Copy)]
#[repr(packed)]
pub(crate) struct Packed<T: Copy>(pub T);
impl<T: Copy> Clone for Packed<T> {
fn clone(&self) -> Self {
*self
}
}
/// Max size of a small str.
///
/// Logic: Value is 24 bytes. 1 byte is for the disciminant. One byte is
/// needed for the small str length.
const SMALL_STR_CAP: usize = 22;
/// Helper to store string data inline.
#[derive(Clone)]
pub(crate) struct SmallStr {
len: u8,
buf: [u8; SMALL_STR_CAP],
}
impl SmallStr {
pub fn try_new(s: &str) -> Option<SmallStr> {
let len = s.len();
if len <= SMALL_STR_CAP {
let mut buf = [0u8; SMALL_STR_CAP];
buf[..len].copy_from_slice(s.as_bytes());
Some(SmallStr {
len: len as u8,
buf,
})
} else {
None
}
}
pub fn as_str(&self) -> &str {
// SAFETY: This is safe because we only place well-formed utf-8 strings
unsafe { std::str::from_utf8_unchecked(&self.buf[..self.len as usize]) }
}
pub fn is_empty(&self) -> bool {
self.len == 0
}
}
#[derive(Clone)]
pub(crate) enum ValueRepr {
Undefined,
Bool(bool),
U64(u64),
I64(i64),
F64(f64),
None,
Invalid(Arc<Error>),
U128(Packed<u128>),
I128(Packed<i128>),
String(Arc<str>, StringType),
SmallStr(SmallStr),
Bytes(Arc<Vec<u8>>),
Object(DynObject),
}
impl fmt::Debug for ValueRepr {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
ValueRepr::Undefined => f.write_str("undefined"),
ValueRepr::Bool(val) => fmt::Debug::fmt(val, f),
ValueRepr::U64(val) => fmt::Debug::fmt(val, f),
ValueRepr::I64(val) => fmt::Debug::fmt(val, f),
ValueRepr::F64(val) => fmt::Debug::fmt(val, f),
ValueRepr::None => f.write_str("none"),
ValueRepr::Invalid(ref val) => write!(f, "<invalid value: {}>", val),
ValueRepr::U128(val) => fmt::Debug::fmt(&{ val.0 }, f),
ValueRepr::I128(val) => fmt::Debug::fmt(&{ val.0 }, f),
ValueRepr::String(val, _) => fmt::Debug::fmt(val, f),
ValueRepr::SmallStr(val) => fmt::Debug::fmt(val.as_str(), f),
ValueRepr::Bytes(val) => {
write!(f, "b'")?;
for &b in val.iter() {
if b == b'"' {
write!(f, "\"")?
} else {
write!(f, "{}", b.escape_ascii())?;
}
}
write!(f, "'")
}
ValueRepr::Object(val) => val.render(f),
}
}
}
impl Hash for Value {
fn hash<H: Hasher>(&self, state: &mut H) {
match &self.0 {
ValueRepr::None | ValueRepr::Undefined => 0u8.hash(state),
ValueRepr::String(ref s, _) => s.hash(state),
ValueRepr::SmallStr(s) => s.as_str().hash(state),
ValueRepr::Bool(b) => b.hash(state),
ValueRepr::Invalid(ref e) => (e.kind(), e.detail()).hash(state),
ValueRepr::Bytes(b) => b.hash(state),
ValueRepr::Object(d) => d.hash(state),
ValueRepr::U64(_)
| ValueRepr::I64(_)
| ValueRepr::F64(_)
| ValueRepr::U128(_)
| ValueRepr::I128(_) => {
if let Ok(val) = i64::try_from(self.clone()) {
val.hash(state)
} else {
as_f64(self, true).map(|x| x.to_bits()).hash(state)
}
}
}
}
}
/// Represents a dynamically typed value in the template engine.
#[derive(Clone)]
pub struct Value(pub(crate) ValueRepr);
impl PartialEq for Value {
fn eq(&self, other: &Self) -> bool {
match (&self.0, &other.0) {
(ValueRepr::None, ValueRepr::None) => true,
(ValueRepr::Undefined, ValueRepr::Undefined) => true,
(ValueRepr::String(ref a, _), ValueRepr::String(ref b, _)) => a == b,
(ValueRepr::SmallStr(a), ValueRepr::SmallStr(b)) => a.as_str() == b.as_str(),
(ValueRepr::Bytes(a), ValueRepr::Bytes(b)) => a == b,
_ => match ops::coerce(self, other, false) {
Some(ops::CoerceResult::F64(a, b)) => a == b,
Some(ops::CoerceResult::I128(a, b)) => a == b,
Some(ops::CoerceResult::Str(a, b)) => a == b,
None => {
if let (Some(a), Some(b)) = (self.as_object(), other.as_object()) {
if a.is_same_object(b) {
return true;
}
match (a.repr(), b.repr()) {
(ObjectRepr::Map, ObjectRepr::Map) => {
// only if we have known lengths can we compare the enumerators
// ahead of time. This function has a fallback for when a
// map has an unknown length. That's generally a bad idea, but
// it makes sense supporting regardless as silent failures are
// not a lot of fun.
let mut need_length_fallback = true;
if let (Some(a_len), Some(b_len)) =
(a.enumerator_len(), b.enumerator_len())
{
if a_len != b_len {
return false;
}
need_length_fallback = false;
}
let mut a_count = 0;
if !a.try_iter_pairs().map_or(false, |mut ak| {
ak.all(|(k, v1)| {
a_count += 1;
b.get_value(&k).map_or(false, |v2| v1 == v2)
})
}) {
return false;
}
if !need_length_fallback {
true
} else {
a_count == b.try_iter().map_or(0, |x| x.count())
}
}
(
ObjectRepr::Seq | ObjectRepr::Iterable,
ObjectRepr::Seq | ObjectRepr::Iterable,
) => {
if let (Some(ak), Some(bk)) = (a.try_iter(), b.try_iter()) {
ak.eq(bk)
} else {
false
}
}
_ => false,
}
} else {
false
}
}
},
}
}
}
impl Eq for Value {}
impl PartialOrd for Value {
fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
Some(self.cmp(other))
}
}
fn f64_total_cmp(left: f64, right: f64) -> Ordering {
// this is taken from f64::total_cmp on newer rust versions
let mut left = left.to_bits() as i64;
let mut right = right.to_bits() as i64;
left ^= (((left >> 63) as u64) >> 1) as i64;
right ^= (((right >> 63) as u64) >> 1) as i64;
left.cmp(&right)
}
impl Ord for Value {
fn cmp(&self, other: &Self) -> Ordering {
let kind_ordering = self.kind().cmp(&other.kind());
if matches!(kind_ordering, Ordering::Less | Ordering::Greater) {
return kind_ordering;
}
match (&self.0, &other.0) {
(ValueRepr::None, ValueRepr::None) => Ordering::Equal,
(ValueRepr::Undefined, ValueRepr::Undefined) => Ordering::Equal,
(ValueRepr::String(ref a, _), ValueRepr::String(ref b, _)) => a.cmp(b),
(ValueRepr::SmallStr(a), ValueRepr::SmallStr(b)) => a.as_str().cmp(b.as_str()),
(ValueRepr::Bytes(a), ValueRepr::Bytes(b)) => a.cmp(b),
_ => match ops::coerce(self, other, false) {
Some(ops::CoerceResult::F64(a, b)) => f64_total_cmp(a, b),
Some(ops::CoerceResult::I128(a, b)) => a.cmp(&b),
Some(ops::CoerceResult::Str(a, b)) => a.cmp(b),
None => {
if let (Some(a), Some(b)) = (self.as_object(), other.as_object()) {
if a.is_same_object(b) {
Ordering::Equal
} else {
match (a.repr(), b.repr()) {
(ObjectRepr::Map, ObjectRepr::Map) => {
// This is not really correct. Because the keys can be in arbitrary
// order this could just sort really weirdly as a result. However
// we don't want to pay the cost of actually sorting the keys for
// ordering so we just accept this for now.
match (a.try_iter_pairs(), b.try_iter_pairs()) {
(Some(a), Some(b)) => a.cmp(b),
_ => unreachable!(),
}
}
(
ObjectRepr::Seq | ObjectRepr::Iterable,
ObjectRepr::Seq | ObjectRepr::Iterable,
) => match (a.try_iter(), b.try_iter()) {
(Some(a), Some(b)) => a.cmp(b),
_ => unreachable!(),
},
(_, _) => unreachable!(),
}
}
} else {
unreachable!()
}
}
},
}
}
}
impl fmt::Debug for Value {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), std::fmt::Error> {
fmt::Debug::fmt(&self.0, f)
}
}
impl fmt::Display for Value {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match &self.0 {
ValueRepr::Undefined => Ok(()),
ValueRepr::Bool(val) => val.fmt(f),
ValueRepr::U64(val) => val.fmt(f),
ValueRepr::I64(val) => val.fmt(f),
ValueRepr::F64(val) => {
if val.is_nan() {
f.write_str("NaN")
} else if val.is_infinite() {
write!(f, "{}inf", if val.is_sign_negative() { "-" } else { "" })
} else {
let mut num = val.to_string();
if !num.contains('.') {
num.push_str(".0");
}
write!(f, "{num}")
}
}
ValueRepr::None => f.write_str("none"),
ValueRepr::Invalid(ref val) => write!(f, "<invalid value: {}>", val),
ValueRepr::I128(val) => write!(f, "{}", { val.0 }),
ValueRepr::String(val, _) => write!(f, "{val}"),
ValueRepr::SmallStr(val) => write!(f, "{}", val.as_str()),
ValueRepr::Bytes(val) => write!(f, "{}", String::from_utf8_lossy(val)),
ValueRepr::U128(val) => write!(f, "{}", { val.0 }),
ValueRepr::Object(x) => write!(f, "{x}"),
}
}
}
impl Default for Value {
fn default() -> Value {
ValueRepr::Undefined.into()
}
}
/// Intern a string.
///
/// When the `key_interning` feature is in used, then MiniJinja will attempt to
/// reuse strings in certain cases. This function can be used to utilize the
/// same functionality. There is no guarantee that a string will be interned
/// as there are heuristics involved for it. Additionally the string interning
/// will only work during the template engine execution (eg: within filters etc.).
///
/// The use of this function is generally recommended against and it might
/// become deprecated in the future.
pub fn intern(s: &str) -> Arc<str> {
#[cfg(feature = "key_interning")]
{
crate::value::string_interning::try_intern(s)
}
#[cfg(not(feature = "key_interning"))]
{
Arc::from(s.to_string())
}
}
/// Like [`intern`] but returns a [`Value`] instead of an `Arc<str>`.
///
/// This has the benefit that it will only perform interning if the string
/// is not already interned.
pub(crate) fn intern_into_value(s: &str) -> Value {
match SmallStr::try_new(s) {
Some(small_str) => Value(ValueRepr::SmallStr(small_str)),
None => Value::from(intern(s)),
}
}
#[allow(clippy::len_without_is_empty)]
impl Value {
/// The undefined value.
///
/// This constant exists because the undefined type does not exist in Rust
/// and this is the only way to construct it.
pub const UNDEFINED: Value = Value(ValueRepr::Undefined);
/// Creates a value from something that can be serialized.
///
/// This is the method that MiniJinja will generally use whenever a serializable
/// object is passed to one of the APIs that internally want to create a value.
/// For instance this is what [`context!`](crate::context) and
/// [`render`](crate::Template::render) will use.
///
/// During serialization of the value, [`serializing_for_value`] will return
/// `true` which makes it possible to customize serialization for MiniJinja.
/// For more information see [`serializing_for_value`].
///
/// ```
/// # use minijinja::value::Value;
/// let val = Value::from_serialize(&vec![1, 2, 3]);
/// ```
///
/// This method does not fail but it might return a value that is not valid. Such
/// values will when operated on fail in the template engine in most situations.
/// This for instance can happen if the underlying implementation of [`Serialize`]
/// fails. There are also cases where invalid objects are silently hidden in the
/// engine today. This is for instance the case for when keys are used in hash maps
/// that the engine cannot deal with. Invalid values are considered an implementation
/// detail. There is currently no API to validate a value.
///
/// If the `deserialization` feature is enabled then the inverse of this method
/// is to use the [`Value`] type as serializer. You can pass a value into the
/// [`deserialize`](serde::Deserialize::deserialize) method of a type that supports
/// serde deserialization.
pub fn from_serialize<T: Serialize>(value: T) -> Value {
let _serialization_guard = mark_internal_serialization();
let _optimization_guard = value_optimization();
transform(value)
}
/// Extracts a contained error.
///
/// An invalid value carres an error internally and will reveal that error
/// at a later point when iteracted with. This is used to carry
/// serialization errors or failures that happen when the engine otherwise
/// assumes an infallible operation such as iteration.
pub(crate) fn validate(self) -> Result<Value, Error> {
if let ValueRepr::Invalid(err) = self.0 {
// Today the API implies tghat errors are `Clone`, but we don't want to expose
// this as a functionality (yet?).
Err(Arc::try_unwrap(err).unwrap_or_else(|arc| (*arc).internal_clone()))
} else {
Ok(self)
}
}
/// Creates a value from a safe string.
///
/// A safe string is one that will bypass auto escaping. For instance if you
/// want to have the template engine render some HTML without the user having to
/// supply the `|safe` filter, you can use a value of this type instead.
///
/// ```
/// # use minijinja::value::Value;
/// let val = Value::from_safe_string("<em>note</em>".into());
/// ```
pub fn from_safe_string(value: String) -> Value {
ValueRepr::String(Arc::from(value), StringType::Safe).into()
}
/// Creates a value from a byte vector.
///
/// MiniJinja can hold on to bytes and has some limited built-in support for
/// working with them. They are non iterable and not particularly useful
/// in the context of templates. When they are stringified, they are assumed
/// to contain UTF-8 and will be treated as such. They become more useful
/// when a filter can do something with them (eg: base64 encode them etc.).
///
/// This method exists so that a value can be constructed as creating a
/// value from a `Vec<u8>` would normally just create a sequence.
pub fn from_bytes(value: Vec<u8>) -> Value {
ValueRepr::Bytes(value.into()).into()
}
/// Creates a value from a dynamic object.
///
/// For more information see [`Object`].
///
/// ```rust
/// # use minijinja::value::{Value, Object};
/// use std::fmt;
///
/// #[derive(Debug)]
/// struct Thing {
/// id: usize,
/// }
///
/// impl Object for Thing {}
///
/// let val = Value::from_object(Thing { id: 42 });
/// ```
pub fn from_object<T: Object + Send + Sync + 'static>(value: T) -> Value {
Value::from(ValueRepr::Object(DynObject::new(Arc::new(value))))
}
/// Like [`from_object`](Self::from_object) but for type erased dynamic objects.
///
/// This especially useful if you have an object that has an `Arc<T>` to another
/// child object that you want to return as a `Arc<T>` turns into a [`DynObject`]
/// automatically.
///
/// ```rust
/// # use std::sync::Arc;
/// # use minijinja::value::{Value, Object, Enumerator};
/// #[derive(Debug)]
/// pub struct HttpConfig {
/// port: usize,
/// }
///
/// #[derive(Debug)]
/// struct Config {
/// http: Arc<HttpConfig>,
/// }
///
/// impl Object for HttpConfig {
/// fn enumerate(self: &Arc<Self>) -> Enumerator {
/// Enumerator::Str(&["port"])
/// }
///
/// fn get_value(self: &Arc<Self>, key: &Value) -> Option<Value> {
/// match key.as_str()? {
/// "port" => Some(Value::from(self.port)),
/// _ => None,
/// }
/// }
/// }
///
/// impl Object for Config {
/// fn enumerate(self: &Arc<Self>) -> Enumerator {
/// Enumerator::Str(&["http"])
/// }
///
/// fn get_value(self: &Arc<Self>, key: &Value) -> Option<Value> {
/// match key.as_str()? {
/// "http" => Some(Value::from_dyn_object(self.http.clone())),
/// _ => None
/// }
/// }
/// }
/// ```
pub fn from_dyn_object<T: Into<DynObject>>(value: T) -> Value {
Value::from(ValueRepr::Object(value.into()))
}
/// Creates a value that is an iterable.
///
/// The function is invoked to create a new iterator every time the value is
/// iterated over.
///
/// ```
/// # use minijinja::value::Value;
/// let val = Value::make_iterable(|| 0..10);
/// ```
///
/// Iterators that implement [`ExactSizeIterator`] or have a matching lower and upper
/// bound on the [`Iterator::size_hint`] report a known `loop.length`. Iterators that
/// do not fulfill these requirements will not. The same is true for `revindex` and
/// similar properties.
pub fn make_iterable<I, T, F>(maker: F) -> Value
where
I: Iterator<Item = T> + Send + Sync + 'static,
T: Into<Value> + Send + Sync + 'static,
F: Fn() -> I + Send + Sync + 'static,
{
Value::make_object_iterable((), move |_| Box::new(maker().map(Into::into)))
}
/// Creates an iterable that iterates over the given value.
///
/// This is similar to [`make_iterable`](Self::make_iterable) but it takes an extra
/// reference to a value it can borrow out from. It's a bit less generic in that it
/// needs to return a boxed iterator of values directly.
///
/// ```rust
/// # use minijinja::value::Value;
/// let val = Value::make_object_iterable(vec![1, 2, 3], |vec| {
/// Box::new(vec.iter().copied().map(Value::from))
/// });
/// assert_eq!(val.to_string(), "[1, 2, 3]");
/// ````
pub fn make_object_iterable<T, F>(object: T, maker: F) -> Value
where
T: Send + Sync + 'static,
F: for<'a> Fn(&'a T) -> Box<dyn Iterator<Item = Value> + Send + Sync + 'a>
+ Send
+ Sync
+ 'static,
{
struct Iterable<T, F> {
maker: F,
object: T,
}
impl<T, F> fmt::Debug for Iterable<T, F> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("<iterator>").finish()
}
}
impl<T, F> Object for Iterable<T, F>
where
T: Send + Sync + 'static,
F: for<'a> Fn(&'a T) -> Box<dyn Iterator<Item = Value> + Send + Sync + 'a>
+ Send
+ Sync
+ 'static,
{
fn repr(self: &Arc<Self>) -> ObjectRepr {
ObjectRepr::Iterable
}
fn enumerate(self: &Arc<Self>) -> Enumerator {
struct Iter {
iter: Box<dyn Iterator<Item = Value> + Send + Sync + 'static>,
_object: DynObject,
}
impl Iterator for Iter {
type Item = Value;
fn next(&mut self) -> Option<Self::Item> {
self.iter.next()
}
fn size_hint(&self) -> (usize, Option<usize>) {
self.iter.size_hint()
}
}
// SAFETY: this is safe because the object is kept alive by the iter
let iter = unsafe {
std::mem::transmute::<
Box<dyn Iterator<Item = _>>,
Box<dyn Iterator<Item = _> + Send + Sync>,
>((self.maker)(&self.object))
};
let _object = DynObject::new(self.clone());
Enumerator::Iter(Box::new(Iter { iter, _object }))
}
}
Value::from_object(Iterable { maker, object })
}
/// Creates a value from a one-shot iterator.
///
/// This takes an iterator (yielding values that can be turned into a [`Value`])
/// and wraps it in a way that it turns into an iterable value. From the view of
/// the template this can be iterated over exactly once for the most part once
/// exhausted.
///
/// Such iterators are strongly recommended against in the general sense due to
/// their surprising behavior, but they can be useful for more advanced use
/// cases where data should be streamed into the template as it becomes available.
///
/// Such iterators never have any size hints.
///
/// ```
/// # use minijinja::value::Value;
/// let val = Value::make_one_shot_iterator(0..10);
/// ```
///
/// Attempting to iterate over it a second time will not yield any more items.
pub fn make_one_shot_iterator<I, T>(iter: I) -> Value
where
I: Iterator<Item = T> + Send + Sync + 'static,
T: Into<Value> + Send + Sync + 'static,
{
let iter = Arc::new(Mutex::new(iter.fuse()));
Value::make_iterable(move || {
let iter = iter.clone();
std::iter::from_fn(move || iter.lock().unwrap().next())
})
}
/// Creates a callable value from a function.
///
/// ```
/// # use minijinja::value::Value;
/// let pow = Value::from_function(|a: u32| a * a);
/// ```
pub fn from_function<F, Rv, Args>(f: F) -> Value
where
// the crazy bounds here exist to enable borrowing in closures
F: functions::Function<Rv, Args>
+ for<'a> functions::Function<Rv, <Args as FunctionArgs<'a>>::Output>,
Rv: FunctionResult,
Args: for<'a> FunctionArgs<'a>,
{
functions::BoxedFunction::new(f).to_value()
}
/// Returns the kind of the value.
///
/// This can be used to determine what's in the value before trying to
/// perform operations on it.
pub fn kind(&self) -> ValueKind {
match self.0 {
ValueRepr::Undefined => ValueKind::Undefined,
ValueRepr::Bool(_) => ValueKind::Bool,
ValueRepr::U64(_) | ValueRepr::I64(_) | ValueRepr::F64(_) => ValueKind::Number,
ValueRepr::None => ValueKind::None,
ValueRepr::I128(_) => ValueKind::Number,
ValueRepr::String(..) | ValueRepr::SmallStr(_) => ValueKind::String,
ValueRepr::Bytes(_) => ValueKind::Bytes,
ValueRepr::U128(_) => ValueKind::Number,
ValueRepr::Invalid(_) => ValueKind::Invalid,
ValueRepr::Object(ref obj) => match obj.repr() {
ObjectRepr::Map => ValueKind::Map,
ObjectRepr::Seq => ValueKind::Seq,
ObjectRepr::Iterable => ValueKind::Iterable,
ObjectRepr::Plain => ValueKind::Plain,
},
}
}
/// Returns `true` if the value is a number.
///
/// To convert a value into a primitive number, use [`TryFrom`] or [`TryInto`].
pub fn is_number(&self) -> bool {
matches!(
self.0,
ValueRepr::U64(_)
| ValueRepr::I64(_)
| ValueRepr::F64(_)
| ValueRepr::I128(_)
| ValueRepr::U128(_)
)
}
/// Returns true if the number is a real integer.
///
/// This can be used to distinguish `42` from `42.0`. For the most part
/// the engine keeps these the same.
pub fn is_integer(&self) -> bool {
matches!(
self.0,
ValueRepr::U64(_) | ValueRepr::I64(_) | ValueRepr::I128(_) | ValueRepr::U128(_)
)
}
/// Returns `true` if the map represents keyword arguments.
pub fn is_kwargs(&self) -> bool {
Kwargs::extract(self).is_some()
}
/// Is this value considered true?
///
/// The engine inherits the same behavior as Jinja2 when it comes to
/// considering objects true. Empty objects are generally not considered
/// true. For custom objects this is customized by [`Object::is_true`].
pub fn is_true(&self) -> bool {
match self.0 {
ValueRepr::Bool(val) => val,
ValueRepr::U64(x) => x != 0,
ValueRepr::U128(x) => x.0 != 0,
ValueRepr::I64(x) => x != 0,
ValueRepr::I128(x) => x.0 != 0,
ValueRepr::F64(x) => x != 0.0,
ValueRepr::String(ref x, _) => !x.is_empty(),
ValueRepr::SmallStr(ref x) => !x.is_empty(),
ValueRepr::Bytes(ref x) => !x.is_empty(),
ValueRepr::None | ValueRepr::Undefined | ValueRepr::Invalid(_) => false,
ValueRepr::Object(ref x) => x.is_true(),
}
}
/// Returns `true` if this value is safe.
pub fn is_safe(&self) -> bool {
matches!(&self.0, ValueRepr::String(_, StringType::Safe))
}
/// Returns `true` if this value is undefined.
pub fn is_undefined(&self) -> bool {
matches!(&self.0, ValueRepr::Undefined)
}
/// Returns `true` if this value is none.
pub fn is_none(&self) -> bool {
matches!(&self.0, ValueRepr::None)
}
/// If the value is a string, return it.
///
/// This will also perform a lossy string conversion of bytes from utf-8.
pub fn to_str(&self) -> Option<Arc<str>> {
match &self.0 {
ValueRepr::String(ref s, _) => Some(s.clone()),
ValueRepr::SmallStr(ref s) => Some(Arc::from(s.as_str())),
ValueRepr::Bytes(ref b) => Some(Arc::from(String::from_utf8_lossy(b))),
_ => None,
}
}
/// If the value is a string, return it.
///
/// This will also return well formed utf-8 bytes as string.
pub fn as_str(&self) -> Option<&str> {
match &self.0 {
ValueRepr::String(ref s, _) => Some(s as &str),
ValueRepr::SmallStr(ref s) => Some(s.as_str()),
ValueRepr::Bytes(ref b) => str::from_utf8(b).ok(),
_ => None,
}
}
/// If this is an i64 return it
pub fn as_usize(&self) -> Option<usize> {
usize::try_from(self.clone()).ok()
}
/// If this is an i64 return it
pub fn as_i64(&self) -> Option<i64> {
i64::try_from(self.clone()).ok()
}
/// Returns the bytes of this value if they exist.
pub fn as_bytes(&self) -> Option<&[u8]> {
match &self.0 {
ValueRepr::String(ref s, _) => Some(s.as_bytes()),
ValueRepr::SmallStr(ref s) => Some(s.as_str().as_bytes()),
ValueRepr::Bytes(ref b) => Some(&b[..]),
_ => None,
}
}
/// If the value is an object a reference to it is returned.
///
/// The returned value is a reference to a type erased [`DynObject`].
/// For a specific type use [`downcast_object`](Self::downcast_object)
/// instead.
pub fn as_object(&self) -> Option<&DynObject> {
match self.0 {
ValueRepr::Object(ref dy) => Some(dy),
_ => None,
}
}
/// Returns the length of the contained value.
///
/// Values without a length will return `None`.
///
/// ```
/// # use minijinja::value::Value;
/// let seq = Value::from(vec![1, 2, 3, 4]);
/// assert_eq!(seq.len(), Some(4));
/// ```
pub fn len(&self) -> Option<usize> {
match self.0 {
ValueRepr::String(ref s, _) => Some(s.chars().count()),
ValueRepr::SmallStr(ref s) => Some(s.as_str().chars().count()),
ValueRepr::Bytes(ref b) => Some(b.len()),
ValueRepr::Object(ref dy) => dy.enumerator_len(),
_ => None,
}
}
/// Looks up an attribute by attribute name.
///
/// This this returns [`UNDEFINED`](Self::UNDEFINED) when an invalid key is
/// resolved. An error is returned if the value does not contain an object
/// that has attributes.
///
/// ```
/// # use minijinja::value::Value;
/// # fn test() -> Result<(), minijinja::Error> {
/// let ctx = minijinja::context! {
/// foo => "Foo"
/// };
/// let value = ctx.get_attr("foo")?;
/// assert_eq!(value.to_string(), "Foo");
/// # Ok(()) }
/// ```
pub fn get_attr(&self, key: &str) -> Result<Value, Error> {
let value = match self.0 {
ValueRepr::Undefined => return Err(Error::from(ErrorKind::UndefinedError)),
ValueRepr::Object(ref dy) => dy.get_value(&Value::from(key)),
_ => None,
};
Ok(value.unwrap_or(Value::UNDEFINED))
}
/// Alternative lookup strategy without error handling exclusively for context
/// resolution.
///
/// The main difference is that the return value will be `None` if the value is
/// unable to look up the key rather than returning `Undefined` and errors will
/// also not be created.
pub(crate) fn get_attr_fast(&self, key: &str) -> Option<Value> {
match self.0 {
ValueRepr::Object(ref dy) => dy.get_value(&Value::from(key)),
_ => None,
}
}
/// Looks up an index of the value.
///
/// This is a shortcut for [`get_item`](Self::get_item).
///
/// ```
/// # use minijinja::value::Value;
/// let seq = Value::from(vec![0u32, 1, 2]);
/// let value = seq.get_item_by_index(1).unwrap();
/// assert_eq!(value.try_into().ok(), Some(1));
/// ```
pub fn get_item_by_index(&self, idx: usize) -> Result<Value, Error> {
self.get_item(&Value(ValueRepr::U64(idx as _)))
}
/// Looks up an item (or attribute) by key.
///
/// This is similar to [`get_attr`](Self::get_attr) but instead of using
/// a string key this can be any key. For instance this can be used to
/// index into sequences. Like [`get_attr`](Self::get_attr) this returns
/// [`UNDEFINED`](Self::UNDEFINED) when an invalid key is looked up.
///
/// ```
/// # use minijinja::value::Value;
/// let ctx = minijinja::context! {
/// foo => "Foo",
/// };
/// let value = ctx.get_item(&Value::from("foo")).unwrap();
/// assert_eq!(value.to_string(), "Foo");
/// ```
pub fn get_item(&self, key: &Value) -> Result<Value, Error> {
if let ValueRepr::Undefined = self.0 {
Err(Error::from(ErrorKind::UndefinedError))
} else {
Ok(self.get_item_opt(key).unwrap_or(Value::UNDEFINED))
}
}
/// Iterates over the value.
///
/// Depending on the [`kind`](Self::kind) of the value the iterator
/// has a different behavior.
///
/// * [`ValueKind::Map`]: the iterator yields the keys of the map.
/// * [`ValueKind::Seq`] / [`ValueKind::Iterable`]: the iterator yields the items in the sequence.
/// * [`ValueKind::String`]: the iterator yields characters in a string.
/// * [`ValueKind::None`] / [`ValueKind::Undefined`]: the iterator is empty.
///
/// ```
/// # use minijinja::value::Value;
/// # fn test() -> Result<(), minijinja::Error> {
/// let value = Value::from({
/// let mut m = std::collections::BTreeMap::new();
/// m.insert("foo", 42);
/// m.insert("bar", 23);
/// m
/// });
/// for key in value.try_iter()? {
/// let value = value.get_item(&key)?;
/// println!("{} = {}", key, value);
/// }
/// # Ok(()) }
/// ```
pub fn try_iter(&self) -> Result<ValueIter, Error> {
match self.0 {
ValueRepr::None | ValueRepr::Undefined => Some(ValueIterImpl::Empty),
ValueRepr::String(ref s, _) => {
Some(ValueIterImpl::Chars(0, s.chars().count(), Arc::clone(s)))
}
ValueRepr::SmallStr(ref s) => Some(ValueIterImpl::Chars(
0,
s.as_str().chars().count(),
Arc::from(s.as_str()),
)),
ValueRepr::Object(ref obj) => obj.try_iter().map(ValueIterImpl::Dyn),
_ => None,
}
.map(|imp| ValueIter { imp })
.ok_or_else(|| {
Error::new(
ErrorKind::InvalidOperation,
format!("{} is not iterable", self.kind()),
)
})
}
/// Returns a reversed view of this value.
///
/// This is implemented for the following types with the following behaviors:
///
/// * undefined or none: value returned unchanged.
/// * string and bytes: returns a reversed version of that value
/// * iterables: returns a reversed version of the iterable. If the iterable is not
/// reversible itself, it consumes it and then reverses it.
pub fn reverse(&self) -> Result<Value, Error> {
match self.0 {
ValueRepr::Undefined | ValueRepr::None => Some(self.clone()),
ValueRepr::String(ref s, _) => Some(Value::from(s.chars().rev().collect::<String>())),
ValueRepr::SmallStr(ref s) => {
// TODO: add small str optimization here
Some(Value::from(s.as_str().chars().rev().collect::<String>()))
}
ValueRepr::Bytes(ref b) => Some(Value::from_bytes(
b.iter().rev().copied().collect::<Vec<_>>(),
)),
ValueRepr::Object(ref o) => match o.enumerate() {
Enumerator::NonEnumerable => None,
Enumerator::Empty => Some(Value::make_iterable(|| None::<Value>.into_iter())),
Enumerator::Seq(l) => {
let self_clone = o.clone();
Some(Value::make_iterable(move || {
let self_clone = self_clone.clone();
(0..l).rev().map(move |idx| {
self_clone.get_value(&Value::from(idx)).unwrap_or_default()
})
}))
}
Enumerator::Iter(iter) => {
let mut v = iter.collect::<Vec<_>>();
v.reverse();
Some(Value::make_object_iterable(v, move |v| {
Box::new(v.iter().cloned())
}))
}
Enumerator::RevIter(rev_iter) => {
let for_restart = self.clone();
let iter = Mutex::new(Some(rev_iter));
Some(Value::make_iterable(move || {
if let Some(iter) = iter.lock().unwrap().take() {
Box::new(iter) as Box<dyn Iterator<Item = Value> + Send + Sync>
} else {
match for_restart.reverse().and_then(|x| x.try_iter()) {
Ok(iterable) => Box::new(iterable)
as Box<dyn Iterator<Item = Value> + Send + Sync>,
Err(err) => Box::new(Some(Value::from(err)).into_iter())
as Box<dyn Iterator<Item = Value> + Send + Sync>,
}
}
}))
}
Enumerator::Str(s) => Some(Value::make_iterable(move || s.iter().rev().copied())),
Enumerator::Values(mut v) => {
v.reverse();
Some(Value::make_object_iterable(v, move |v| {
Box::new(v.iter().cloned())
}))
}
},
_ => None,
}
.ok_or_else(|| {
Error::new(
ErrorKind::InvalidOperation,
format!("cannot reverse values of type {}", self.kind()),
)
})
}
/// Returns some reference to the boxed object if it is of type `T`, or None if it isn’t.
///
/// This is basically the "reverse" of [`from_object`](Self::from_object)
/// and [`from_dyn_object`](Self::from_dyn_object). It's also a shortcut for
/// [`downcast_ref`](DynObject::downcast_ref) on the return value of
/// [`as_object`](Self::as_object).
///
/// # Example
///
/// ```rust
/// # use minijinja::value::{Value, Object};
/// use std::fmt;
///
/// #[derive(Debug)]
/// struct Thing {
/// id: usize,
/// }
///
/// impl Object for Thing {}
///
/// let x_value = Value::from_object(Thing { id: 42 });
/// let thing = x_value.downcast_object_ref::<Thing>().unwrap();
/// assert_eq!(thing.id, 42);
/// ```
pub fn downcast_object_ref<T: 'static>(&self) -> Option<&T> {
match self.0 {
ValueRepr::Object(ref o) => o.downcast_ref(),
_ => None,
}
}
/// Like [`downcast_object_ref`](Self::downcast_object_ref) but returns
/// the actual object.
pub fn downcast_object<T: 'static>(&self) -> Option<Arc<T>> {
match self.0 {
ValueRepr::Object(ref o) => o.downcast(),
_ => None,
}
}
pub(crate) fn get_item_opt(&self, key: &Value) -> Option<Value> {
fn index(value: &Value, len: impl Fn() -> Option<usize>) -> Option<usize> {
match value.as_i64().and_then(|v| isize::try_from(v).ok()) {
Some(i) if i < 0 => some!(len()).checked_sub(i.unsigned_abs()),
Some(i) => Some(i as usize),
None => None,
}
}
match self.0 {
ValueRepr::Object(ref dy) => match dy.repr() {
ObjectRepr::Map | ObjectRepr::Plain => dy.get_value(key),
ObjectRepr::Iterable => {
if let Some(rv) = dy.get_value(key) {
return Some(rv);
}
// The default behavior is to try to index into the iterable
// as if nth() was called. This lets one slice an array and
// then index into it.
if let Some(idx) = index(key, || dy.enumerator_len()) {
if let Some(mut iter) = dy.try_iter() {
if let Some(rv) = iter.nth(idx) {
return Some(rv);
}
}
}
None
}
ObjectRepr::Seq => {
let idx = index(key, || dy.enumerator_len()).map(Value::from);
dy.get_value(idx.as_ref().unwrap_or(key))
}
},
ValueRepr::String(ref s, _) => {
let idx = some!(index(key, || Some(s.chars().count())));
s.chars().nth(idx).map(Value::from)
}
ValueRepr::SmallStr(ref s) => {
let idx = some!(index(key, || Some(s.as_str().chars().count())));
s.as_str().chars().nth(idx).map(Value::from)
}
ValueRepr::Bytes(ref b) => {
let idx = some!(index(key, || Some(b.len())));
b.get(idx).copied().map(Value::from)
}
_ => None,
}
}
/// Calls the value directly.
///
/// If the value holds a function or macro, this invokes it. Note that in
/// MiniJinja there is a separate namespace for methods on objects and callable
/// items. To call methods (which should be a rather rare occurrence) you
/// have to use [`call_method`](Self::call_method).
///
/// The `args` slice is for the arguments of the function call. To pass
/// keyword arguments use the [`Kwargs`] type.
///
/// Usually the state is already available when it's useful to call this method,
/// but when it's not available you can get a fresh template state straight
/// from the [`Template`](crate::Template) via [`new_state`](crate::Template::new_state).
///
/// ```
/// # use minijinja::{Environment, value::{Value, Kwargs}};
/// # let mut env = Environment::new();
/// # env.add_template("foo", "").unwrap();
/// # let tmpl = env.get_template("foo").unwrap();
/// # let state = tmpl.new_state(); let state = &state;
/// let func = Value::from_function(|v: i64, kwargs: Kwargs| {
/// v * kwargs.get::<i64>("mult").unwrap_or(1)
/// });
/// let rv = func.call(
/// state,
/// &[
/// Value::from(42),
/// Value::from(Kwargs::from_iter([("mult", Value::from(2))])),
/// ],
/// ).unwrap();
/// assert_eq!(rv, Value::from(84));
/// ```
///
/// With the [`args!`](crate::args) macro creating an argument slice is
/// simplified:
///
/// ```
/// # use minijinja::{Environment, args, value::{Value, Kwargs}};
/// # let mut env = Environment::new();
/// # env.add_template("foo", "").unwrap();
/// # let tmpl = env.get_template("foo").unwrap();
/// # let state = tmpl.new_state(); let state = &state;
/// let func = Value::from_function(|v: i64, kwargs: Kwargs| {
/// v * kwargs.get::<i64>("mult").unwrap_or(1)
/// });
/// let rv = func.call(state, args!(42, mult => 2)).unwrap();
/// assert_eq!(rv, Value::from(84));
/// ```
pub fn call(&self, state: &State, args: &[Value]) -> Result<Value, Error> {
if let ValueRepr::Object(ref dy) = self.0 {
dy.call(state, args)
} else {
Err(Error::new(
ErrorKind::InvalidOperation,
format!("value of type {} is not callable", self.kind()),
))
}
}
/// Calls a method on the value.
///
/// The name of the method is `name`, the arguments passed are in the `args`
/// slice.
pub fn call_method(&self, state: &State, name: &str, args: &[Value]) -> Result<Value, Error> {
match self._call_method(state, name, args) {
Ok(rv) => Ok(rv),
Err(mut err) => {
if err.kind() == ErrorKind::UnknownMethod {
if let Some(ref callback) = state.env().unknown_method_callback {
return callback(state, self, name, args);
} else if err.detail().is_none() {
err.set_detail(format!("{} has no method named {}", self.kind(), name));
}
}
Err(err)
}
}
}
fn _call_method(&self, state: &State, name: &str, args: &[Value]) -> Result<Value, Error> {
if let Some(object) = self.as_object() {
object.call_method(state, name, args)
} else {
Err(Error::from(ErrorKind::UnknownMethod))
}
}
#[cfg(feature = "builtins")]
pub(crate) fn get_path(&self, path: &str) -> Result<Value, Error> {
let mut rv = self.clone();
for part in path.split('.') {
if let Ok(num) = part.parse::<usize>() {
rv = ok!(rv.get_item_by_index(num));
} else {
rv = ok!(rv.get_attr(part));
}
}
Ok(rv)
}
#[cfg(feature = "builtins")]
pub(crate) fn get_path_or_default(&self, path: &str, default: &Value) -> Value {
match self.get_path(path) {
Err(_) => default.clone(),
Ok(val) if val.is_undefined() => default.clone(),
Ok(val) => val,
}
}
}
impl Serialize for Value {
fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
where
S: Serializer,
{
// enable round tripping of values
if serializing_for_value() {
let handle = LAST_VALUE_HANDLE.with(|x| {
// we are okay with overflowing the handle here because these values only
// live for a very short period of time and it's not likely that you run out
// of an entire u32 worth of handles in a single serialization operation.
// This lets us stick the handle into a unit variant in the serde data model.
let rv = x.get().wrapping_add(1);
x.set(rv);
rv
});
VALUE_HANDLES.with(|handles| handles.borrow_mut().insert(handle, self.clone()));
return serializer.serialize_unit_variant(
VALUE_HANDLE_MARKER,
handle,
VALUE_HANDLE_MARKER,
);
}
match self.0 {
ValueRepr::Bool(b) => serializer.serialize_bool(b),
ValueRepr::U64(u) => serializer.serialize_u64(u),
ValueRepr::I64(i) => serializer.serialize_i64(i),
ValueRepr::F64(f) => serializer.serialize_f64(f),
ValueRepr::None | ValueRepr::Undefined | ValueRepr::Invalid(_) => {
serializer.serialize_unit()
}
ValueRepr::U128(u) => serializer.serialize_u128(u.0),
ValueRepr::I128(i) => serializer.serialize_i128(i.0),
ValueRepr::String(ref s, _) => serializer.serialize_str(s),
ValueRepr::SmallStr(ref s) => serializer.serialize_str(s.as_str()),
ValueRepr::Bytes(ref b) => serializer.serialize_bytes(b),
ValueRepr::Object(ref o) => match o.repr() {
ObjectRepr::Plain => serializer.serialize_str(&o.to_string()),
ObjectRepr::Seq | ObjectRepr::Iterable => {
use serde::ser::SerializeSeq;
let mut seq = ok!(serializer.serialize_seq(o.enumerator_len()));
if let Some(iter) = o.try_iter() {
for item in iter {
ok!(seq.serialize_element(&item));
}
}
seq.end()
}
ObjectRepr::Map => {
use serde::ser::SerializeMap;
let mut map = ok!(serializer.serialize_map(None));
if let Some(iter) = o.try_iter_pairs() {
for (key, value) in iter {
ok!(map.serialize_entry(&key, &value));
}
}
map.end()
}
},
}
}
}
/// Utility to iterate over values.
pub struct ValueIter {
imp: ValueIterImpl,
}
impl Iterator for ValueIter {
type Item = Value;
fn next(&mut self) -> Option<Self::Item> {
match &mut self.imp {
ValueIterImpl::Empty => None,
ValueIterImpl::Chars(offset, len, ref s) => {
(s as &str)[*offset..].chars().next().map(|c| {
*offset += c.len_utf8();
*len -= 1;
Value::from(c)
})
}
ValueIterImpl::Dyn(iter) => iter.next(),
}
}
fn size_hint(&self) -> (usize, Option<usize>) {
match self.imp {
ValueIterImpl::Empty => (0, Some(0)),
ValueIterImpl::Chars(_, len, _) => (0, Some(len)),
ValueIterImpl::Dyn(ref iter) => iter.size_hint(),
}
}
}
impl fmt::Debug for ValueIter {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("ValueIterator").finish()
}
}
enum ValueIterImpl {
Empty,
Chars(usize, usize, Arc<str>),
Dyn(Box<dyn Iterator<Item = Value> + Send + Sync>),
}
impl From<Error> for Value {
fn from(value: Error) -> Self {
Value(ValueRepr::Invalid(Arc::new(value)))
}
}
#[cfg(test)]
mod tests {
use super::*;
use similar_asserts::assert_eq;
#[test]
fn test_dynamic_object_roundtrip() {
use std::sync::atomic::{self, AtomicUsize};
#[derive(Debug, Clone)]
struct X(Arc<AtomicUsize>);
impl Object for X {
fn get_value(self: &Arc<Self>, key: &Value) -> Option<Value> {
match key.as_str()? {
"value" => Some(Value::from(self.0.load(atomic::Ordering::Relaxed))),
_ => None,
}
}
fn enumerate(self: &Arc<Self>) -> Enumerator {
Enumerator::Str(&["value"])
}
fn render(self: &Arc<Self>, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "{}", self.0.load(atomic::Ordering::Relaxed))
}
}
let x = Arc::new(X(Default::default()));
let x_value = Value::from_dyn_object(x.clone());
x.0.fetch_add(42, atomic::Ordering::Relaxed);
let x_clone = Value::from_serialize(&x_value);
x.0.fetch_add(23, atomic::Ordering::Relaxed);
assert_eq!(x_value.to_string(), "65");
assert_eq!(x_clone.to_string(), "65");
}
#[test]
fn test_string_char() {
let val = Value::from('a');
assert_eq!(char::try_from(val).unwrap(), 'a');
let val = Value::from("a");
assert_eq!(char::try_from(val).unwrap(), 'a');
let val = Value::from("wat");
assert!(char::try_from(val).is_err());
}
#[test]
#[cfg(target_pointer_width = "64")]
fn test_sizes() {
assert_eq!(std::mem::size_of::<Value>(), 24);
}
}